The present invention relates to a screw rotor machine, and in particular to a screw rotor compressor.
Screw rotor machines are chiefly used as compressors for compressing gas, normally air, and to a lesser extent for expanding a compressed gas.
U.S. Pat. No. 3,975,123 teaches a screw compressor whose screw rotors are lubricated, cooled and sealed with water. The rotor trunnions are mounted on bearings that are lubricated with oil in a conventional manner.
The drawback with this construction is that axial seals between the oil-lubricated part and the oil-free part can burst or oil can leak to the oil-free part in some other way. An oil leakage of this nature will contaminate the gas with oil.